The Age of Radiance by Craig Nelson

Langevin, Einstein was equally fulsome:“In his scientific thinking Langevin possessed an extraordinary vivacity and clarity . . . it seems to be certain that he would have developed the special theory of relativity if it had not been done elsewhere.”
    Paul was brilliant, passionate about science, and good-looking. It was a wonderful match for the brokenhearted widow, but Langevin was also married, to Emma Jeanne Desfosses, a harridan who never tired of warmongering in the name of love. In their first year of marital unbliss, Desfosses’s mother and sister took letters from the newlywed husband’s pockets that described his troubled marriage so that Jeanne would have evidence in case of divorce. The following year, he appeared at the lab covered in bruises—during a fracas, the three women had thrown an iron chair at him. But M. Langevin was no bystander in this eternal drama, for when Jeanne stormed out after one fight and threatened to end the marriage, Paul begged her to return . . . a scenario that would be repeated endlessly over the years to come. Sorbonne physicist Jean Perrin and his wife, Henriette, were close with both the Curies and the Langevins, and after one violent spat Henriette recounted,“Often, during meals, M. Langevin, cruelly wounded by the words of his wife, left the table. The meal continued. . . . I was very sad to see the unhappiness of a friend that I liked with all my heart. . . . He said to me, ‘I don’t know who I can lean on. I have only my children and they are very small.’ ”
    In the spring of 1910, Marie, having heard Jeanne’s tales of how her husband woefully mistreated her, criticized Paul to his face for his vile behavior. Langevin replied that she only knew half of the story; that in fact just the other day, Jeanne had cracked a bottle on his head. Paul now found someone to lean on, regularly confiding in Marie about his terrible domestic conundrum—then suddenly, everything between them changed. Marie wrote,“I spent last evening and night thinking of you and the hours we had together. I hold the delicious memory. Still I see your eyes, kind and tender, and your warm smile and I can only dream of the moment that I find again the sweetness of your presence.” He replied, “I am trembling with impatience at the thought of seeing you return at last, and of telling you how much I missed you. I kiss you tenderly awaiting tomorrow.”
    On July 15, 1910, Paul and Marie secretly rented an apartment together, at 5 rue du Banquier. They called it chez nous . Almost immediately, one of Jeanne’s servants fished a love letter from Paul to Marie out of the postal box and gave it to the wife. During their next brawl, she warned him,“You are going to see quite a scandal in the newspapers,” and asked their son, eleven years old, if he wanted to grow up to be like his father and cheat on his wife with a mistress. Marie told the Perrins that her and Paul’s “great friendship angered Mme. Langevin [and] that she had declared to her husband that she was going to get rid of this obstacle.” Paul explained to his lover, “That means that she would kill you.” Marie: “As long as I know you are near her my nights are atrocious. I cannot sleep. With the greatest difficulty I fall asleep at two or three o’clock and awake with the sensation of fever. I cannot even work. . . . I must be attached to you by very strong cords to make up my mind to preserve these cords at the risk of my position and my life.”
    The following week, Jean Perrin “was astounded to see Mme. Curie run to me as I was entering the house. She had been waiting for me for several hours. . . . She said that she had been insulted in the street in crude terms by Mme. Langevin and by her sister, Mme. Bourgeois, and that this woman had threatened her [and demanded that Marie] leave France. . . . I think I will never forget the emotion I felt seeing the distress to which this illustrious woman